Method of creating and maintaining a vacuum



March 9 1926.

G. L. KENNEDY Original Filed Feb. 25, 1924 H 2 PUMP v fig 5 :5 7a.

a- R- 9 98 3 8a 8a INVENTOR.

Guy L. Kennedy BY TTORNEY Patented Mar. 9, 1926.

GUY L. KENNEDY, or New YORK, N. 'ASSIGNOB. '10 KEN-CR1]? CORPORATION, OF

UNITED STATES PATENT OFFICE.

NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF CREATING AND MAINTAINING A VACUUM.

Original application filed February 23, 1924, Serial No. 694,792. Divided and this application filed August 3, 1925.

To all whom it may concern:

Be it known that I, GUYIJ. KENNEDY, a citizen of the United States, residing at New York, in the county of Bronx and 5 State of New York, have invented certain new and useful Improvements in Methods of Creating and Maintaining a Vacuum, of which the following is a specification.

My invention pertains to a method or process for creating and maintaining a vacuum; and has for its object to-produce a vacuum and keep the vacuum substantially constant in the midst of influences and conditions that tend to make the vacuum a variable 5 one. r

The nature and advantages of my invention will appear from the following description and accompanying drawings; and I of course reserve the right to make any changes in the structure used or manner of proceeding adopted, without departing from the scope and spirit of my invention as'thesame is defined by the broad meaning of the terms of the appended claims.

'On the drawings: I V

Figure 1 is a diagrammatic view to explain the principle of my invention; and Figure'2 is'a view of a construction by which my invention can bepracticed. The same numerals identify the same parts throughout.

Figure 1 is a longitudinal sectional view through a casing 1, having an inlet valve 2, a permanently open inlet port 3, and a tube 4, mounted in the casing, and closed at one end except for the inlet 3; the other end of the tube being open and being approximately in the middle of the casing. Connected to the casing is an exhaust or suction 0 pump to draw the air out of the casing 1.

Suppose the valve 2 to be closed and for the moment no inlet port 3 to be present. Then with the pump operating one might produce a-vacuum equal to'say 18 inches of mercury displacement in the casing 1, that is to'say if a manometer-or U-shaped tube T containingmercury has the upper end of one arm in communication with the casing and the upper e'nd ot theother arm open to the atmosphere,the difierence'of level of the mercury in the two arms will be -18-inches.

If new one opens ,theair inlet 2 to admit air, the vacuum in tl e'casing 1 drops-from Serial No. 47,864.

.18 inches of mercury displacement to zero in direct ratio with the extentto which the inlet 2 is opened. My aim is to create within the casing 1 a point or small space,where the vacuum shall besubstantially constantly equal to say 2 inches of mercury displacement regardless of the degree of vacuum 111 the remainder of the casing 1.. Of course ifthe valve 2 is small enough or at least v be extracted by the pump too fast for air coming in through the inlet this vacuum.

Suppose now the small open air inlet 3 is provided, the pump'continuing'to run and 2 to obviate valve 2 being closed as ,m-uchas necessary.

Then inside of the casing 1 will be a small space adjacent the port 3 where the vacuum has dropped to approximately 2 inches of mercury displacement, while still remaining equivalent to 18 inches in the remainder of the casing. If the tube t be mounted inside the casing, with one open end substantially at the middle of the casing and the other end open only to the inlet ,8, it will befound that, if the vacuum in the casing remains, equivalent to 18 inches of mercury displacement, the vacuum in tubet will be substantially constantly equal to 2 inches of mercury displacement.

If new inlet 2 be again'opened to admit enough air into the casing 1, the vacuum in the casing will drop with the opening of inlet 2 more and more, as has been shown, to zero.

drop until the vacuum in the casing has dropped to about 2 inches of mercury displacement.

It is evident, therefore, that this simple" Then the vacuum in tube 4 must also'drop to zero but it does not begin to i device will maintain a substantially constant vacuum within tube 4 until the vacuum in the casing 1 falls below, 2 :inches of mercury displacement; and that from this point-down. to zero, the vacuum in the tube 4 is subject to the same variation as the vacuum in the casing 1;

If, them-one is to establish say a 2-inch vacuum within tube 4, such that itwill .remain constantlyat 2 inches of mercury displacement, plainly some means must be found to increase the vacuum within tube 4, after or at the instant the vacuum in the vessel or casing 1 drops to 2 inches.

This end is gained by the construction shown in Figure 2. The casing 1 is utilized as before with a pumpto exhaust air from the interior thereof. Mounted inside the casing is a tube a. communicating with the atmosphere outside the casing through a small open port 3. Surrounding the tube 4 inside thecasing is a larger tube 5 and. 6 are inlet ports in the wall of the casing leading to the annular space between the tubes 4 and 5. The inner end of this space inside the casing is closed by the coneshaped ring valve 2", which rests against the ends of the tubes 5 and 6. Guide rods 7 are affixed to this valve and pass through to the outside of the casing where they terminate in heads 8 between which and the exterior of the casing are springs 9 to hold the valve 2 normally against the inner extremities of the tubular elements 4- and 5, and close the space between the tubes 4. and 5.

Now with the pump running, and a vacuum of 18 inches of mercury displacement in the casing, a vacuum of 2 inches of mercury displacement will exist in the tube 4; adjacent the inlet 8. If the valve 2 is caused or allowed by any means or in any'manner to lift or open, as by mechanical means pushing against the heads 8 of the rods 7 to overcome the springs 9 and thus open the valve 2 more or less, with resultant variation of pressure conditions to change the vacuum in the casing 1, the vacuum in the casing will: drop because air fiows inthrough the ports 6, the same as through the valve 2 in Figure 1, and through the annular space between the tubes 4 and 5 past the inner ends of these tubes. The flow of air past the inner end of the tube 4 has an aspirating action on this tube, and as a result the vacuum in this tube remains substantially constant and equal to about 2 inches of mercury displacement at least in proximityv to the small port 3, even when thevacuum in the rest of the casing 1 falls to zero. This fact has been estal lished by repeated laboratory tests. Hence I obtain a substantially constant degree of vacuum in the tube. 4, inspite of conditions or influences tending to lower or entirely obliterate the vacuum in the remaining part of the casing 1.

In practice, the opening of the valve 2 may be controlled by hand, as when'the principle of my invention is embodied in a carburetor for an internal combustion engine which acts the same as the pump connected to the casing 1.

The substantially constant vacuum can be produced as above described with either air or liquid admitted by way of inlet 3, provided the liquid is such as to volatilize quickly in the element 4.

This application is a division of my copending application, for patent method and apparatus for maintaining a vacuum, Serial No. 69%.792, filed Feb. 2%), 1924i, and patented as of August 1th, 1925.

Having describedmy invention, what 1 believe to be new and desire to secure and )rotect by Letters Patent of the United tates is 1. The method of producing a substantially constant vacuum in the midst oi conditions of varying pressure tending to alter said vacuum, which consists in creating a vacuum of a )redetermined degree and utilizing the eect of said varying pressure to maintain the predetermined vacuum substantially constant.

2. The method of producing a substantially constant vacuum which consists in causing a gaseous medium under varying pres sure to flow past an enclosed space having an outlet which delivers to said medium, and having an inlet of pro-determined area, the flow of said medium past said outlet exerting an aspirating action in said space which creates and maintains a SllbSbitIltltLlLV constant vacuum therein.

3. The method of producing a substantially constant vacuum which consists in causing a gaseous medium under conditions oi? varying pressure, to pass an enclosed space having an outlet opening delivering to the said medium, and having an inlet opening of predetermined area, thus enabling said medium to exert an aspirating action on said space and maintain a substantially constant vacuum therein, and regulating the volume of said flowing gaseous medium as required.

4. The method of producing a substantially constant'degree of vacuum, which consists in keeping a defined space in com- .munication with the source of supply of the medium to be rarefied, permitting said medium to issue freely from said space, and creating a variable partial vacuum adjacent the point of issuance of said medium from said space and outside of same, so that owing to the effect of said variable, partial vacuum on pressure-conditions in said space, a substantially constant degree of vacuum is obtained therein.

5. The process of creating a substantially constant degree of relatively low pressure or vacuum in a gaseous medium, which consists in maintaining communication between the medium to .be rarefied and a separate mass of a similar medium in proximity thereto, and keeping said second medium in motion while its relative pressure may vary, so that the medium to be: rarefied is subjected pneumatically to the action of saidupon ,oonstant degree of relatively low pressure or vacuum in a gaseous medium, which consists in maintaining communication between the medium to be rarefied and a separate and larger mass of a similar medium in 10 proximity thereto, and keeping said larger mass in motion While its pressure may vary, so that the medium to be rarefied is pneumatically influenced by the larger mass of the similar medium, and its pressure rendered substantially constant, regardless of variations in the pressure of the other medium.

In testimony whereof I affix-my signature.

GUY L. KENNEDY. 

